Single Nucleotide Polymorphisms in DNA Repair Genes (XRCC1, XRCC2, XRCC3) and Their Association with Radiotherapy Toxicity among Head and Neck Cancer Patients:A Study from South-Western Maharashtra.

BACKGROUND

The genetic polymorphisms in DNA repair genes and their correlation with normal tissue toxicity in response to radiation therapy has not been consistently proven in many of the studies done in head and neck cancers (HNC). This study was intended to investigate the association of most common single nucleotide polymorphisms of DNA repair genes with acute radiation induced toxicities such as skin reactions and oral mucositis in normal tissue from HNC patients receiving radiotherapy from South-Western Maharashtra.

METHODS

Two hundred HNC patients receiving radiotherapy were enrolled in this study and the radiation injuries in the form of skin reactions and oral mucositis were recorded. Three single nucleotide polymorphisms (SNPs) rs1799782, rs25489) rs25487 of XRCC1 gene, rs3218536in XRCC2 gene and rs861539 SNP of XRCC3 gene were studied by PCR-RFLP and direct DNA sequencing.  Results: The univariate analysis of SNPs of XRCC1, XRCC2 and XRCC3, the obtained results verified that XRCC1 polymorphism at 194Trp of exon 6 (OR=0.69, 95% CI: 0.28-1.71; p=0.433), codon 280 at exon 9 ((OR=1.05, 95% CI: 0.42-2.63; p=0.911) and codon 399 of at exon 10(OR=1.06, 95% CI: 0.52-2.15; p=0.867) and XRCC2 polymorphism at codon 188 at exon 3 (OR=1.07, 95% CI: 0.46-2.47; p=0.866) and 241Met variant genotype of XRCC3 (OR=2.63 95% CI: 0.42-16.30; p=0.298) showed no association with degree of radiotherapy associated dermatitis or mucositis in HNC patients.

CONCLUSION

The findings from this study postulated that none of rs1799782, rs25489, rs25487 SNPs of XRCC1, rs3218536 SNP of XRCC2 nor rs861539 SNP of XRCC3 were associated with increased toxicity of radiotherapy in HNC patients of south-western Maharashtra. 
.